Hello. Lately i've come across a post:"...you can replace them with stainless rather than the cheesy monkey metal that some are made of these days. Don't replace caliper & suspension bolts with stainless unless it's A4 grade or better, it's hard but brittle & can snap under load."
I feel it is in all our interest to clarify the practicality of using SS fasteners. SS fasteners have a few good merrits: They are shiny and never rust, and i even have them on my bike. The practicality of these fasteners ends there. SS bolts have a low tensile strength equivilent to Gd.2 SAE, what someone might call monkey-metal For most situations this is fine, like anything threaded into aluminum or magnesium. Most likely the thread would strip before the bolt breaks. As someone mentioned before, never use these fasteners for stressed items, like brakes, suspension and sub-frames. These bolts, imho, should be a minimum Gr.8 SAE or Gr. 10.9 metric. Also, in the off-chance you might break one of these bolts, it's still possible to drill and use an easy-out. Try this with SS, there's a good chance the metal will work-harden, making it harder than the drillbit you are using
SS fasteners come in two grades:A2 and A4. A2 stainless is #314stainless, used in regular aplications. A4 stainless is #316 stainless, used for salt-water (marine) aplications. Both grades are equivilent to Gr.2 SAE hardness, which is next to mild steel.
Metric fasteners have their hardness grade stamped ot the head of the bolt eg. "8.8, 10.9, etc" SAE bolts have a number of slashes on the head. Count the slashes and add 2 eg." 6 slashes is a grade 8" Grade 5,8,10 SAE are equal to 8.8, 10.9, 12.9 metric respectively.
I only use SS for its good looks and corrosion resistance. I've also broken enough to know what a pain in the ass they are to remove. Once they get hot enough, they become super hard and brittle.
I hope this post helps the few of you who might be , well...screwed!
Good luck!